权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

A Study on the Application of Non-azeotropic Refrigerant Mixtures in High Temperature Heat Pumps

非共沸混合制冷剂在高温热泵中的应用研究

基本信息

批准号：
61460104
负责人：
SAITO Takamoto
金额：
$ 4.35万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1987
项目状态：
已结题

项目摘要

In comparison with conventional single-component refrigerants, the application of refrigerant mixtures in high temperature heat pumps may result in a higher coefficient of performance, lower condensing pressure, and higher reliability. But it is well known that the boiling and condensation heat transfer coefficients of binary mixtures are reduced due to the mass transfer effects compared with single-component refrigerants. Main purpose of this study is to evaluate the effect of the reduction in heat transfer coefficients on the heat pump performance.Simple models for evaluating the mass transfer effects on boiling heat transfer and condensation heat transfer were developed. In both boiling and condensation heat transfer, mass diffusion layer near the gas-liquid interface causes the increase in heat transfer resistance.In order to confirm the theories mentioned above and to investigate the feasibility of refrigerant mixtures, a heat pump test rig was constructed, which consisted of water-cooled or -heated counterflow heat exchangers and an open type compressor. The COP and the heat transfer performance for the pure refrigerants R12 and R22 and the mixtures R22 with R114 in different compositions were measured. Within the experimental conditions, the reduction in the boiling heat transfer coefficients was more serious than the condensation heat transfer coefficients. The comparison between the theoretical and experimental results of heat transfer coefficients was satisfactorily good. When the heat transfer area of heat exchangers is large enough and the temperature increase of the heat sink fluid at the condenser is large, the COP can increase.

与传统的单组分制冷剂相比，混合制冷剂在高温热泵中的应用可导致更高的性能系数、更低的冷凝压力和更高的可靠性。但由于传质效应的存在，二元混合工质的沸腾和冷凝换热系数比单组分工质的要小。本文主要研究传热系数的降低对热泵性能的影响，建立了简单的传热模型，计算了传热系数的降低对沸腾传热和冷凝传热的影响。在沸腾和冷凝传热过程中，气液界面附近的质量扩散层会引起传热阻力的增加，为了验证上述理论，考察混合工质的可行性，搭建了由水冷或自热式逆流换热器和开式压缩机组成的热泵实验台。测量了纯制冷剂R12和R22以及不同组成的R22与R114混合物的COP和传热性能。在本实验条件下，沸腾换热系数的降低比冷凝换热系数的降低更为严重。传热系数的理论计算值与实验值的比较令人满意。当换热器的传热面积足够大时，冷凝器处的热沉流体的温度升高较大，可以提高COP。